1. Field of the Invention
The invention deals with the field of lighting and/or of signaling, notably for motor vehicles. More particularly, the invention deals with the cooling of the light modules producing these lighting and/or signaling functions.
2. Description of the Related Art
A motor vehicle is equipped with headlights, intended to illuminate the road in front of the vehicle, at night or in conditions of a reduced brightness, by a global light beam. These headlights comprise one or more light modules adapted to generate and direct an intermediate light beam, the addition of which forms said global light beam.
Light modules are known that are formed by two half-shells assembled on a planar support and respectively bearing optical deflection means for the light rays emitted by a light source associated with each half-shell. The rays are deflected toward a projection optical device arranged at the output of the light module. Depending on the light source which is on, a beam is thus produced as the output of the light module that is suitable for creating a high-beam type light, more strongly illuminating the road scene but with the risk of dazzling an oncoming driver, or a low-beam type light, in which the beam is concentrated in front of the vehicle to avoid this type of dazzle.
It has been observed over a number of years that the use of light-emitting diodes as light sources has become widespread in the headlights installed in motor vehicles. Now, it is known that the optical performance of such an assembly can be a function of the operating temperature of the light-emitting diode.
It has also been observed that plastic materials, for example polycarbonate plastic, is being used increasingly regularly for the production of the half-shells forming these light modules, and that this also falls within a context of light module bulk reduction. The combination of these characteristics of compactness, of materials and of use of heat-generating diodes promotes a heating-up of the device that is not compatible with the desired optical performance. A confinement of the hot air between the reflector of the top half-shell and the planar support of the associated light source is in particular observed.